1. Field of the Invention
The invention relates to a method for the production of corrosion-inhibiting coatings on metallic surfaces, according to which monomeric phenols and low molecular condensation products of formaldehyde and ammonia or amines are applied onto the pretreated surface and cured under heat.
2. Prior Art
According to conventional methods, metalic surfaces are coated with finished polymers by lacquering, immersing, spraying, powder application and the like. With phenol/formaldehyde condensation products, however, only relatively thick and porous coatings can be produced by these methods.
It is known from German Pat. No. 27 12 903 that thin anticorrosive coatings consisting of condensation products of phenols with low molecular condensation products of formaldehyde with ammonia or amines can be produced on metallic surfaces by evaporation. Thereby a very homogeneous distribution of the individual components on metallic surfaces can be obtained. This, during the curing step, results in non-porous coatings. However, the major drawbacks of this method are that considerable resources pertaining to the apparatus are necessary and that coatings can only be produced on surfaces which can readily be cooled.